When humans are happy, they may smile, or laugh, or dance - but what do animals do? Melissa, age 12, wants to know how she can tell if her cat is happy and likes you.

The mass of the Earth is big enough that the gravitational force it creates can pull the hard shape of ice, rock and metal into a sphere.
NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight CenterSeptember 19, 2017

Niamh, age 7, wants to know why we have scary dreams. But after 200 years of study, dreams are still very much a mystery.

Lasers being shone from the European Southern Observatory’s Very Large Telescope in Chile.
These lasers help remove the twinkles in the night sky and help astronomers see stars clearer on Earth than ever before.
F. Kamphues/ESOSeptember 3, 2017

Taste dictates most food choices, but there's more to it than just the taste buds on your tongue.

The edges of your lost tooth are sharp because when the root of the baby tooth is being eaten away, it tends to start from the middle of the root. That leaves a sharp edge behind when the tooth breaks off.
Flickr/Stephanie YoungJune 27, 2017